Construction machine with rotor load monitoring

ABSTRACT

A machine for road work for road work, the machine can comprise: a frame, a drive system including a power source carried by the frame, a milling system driven by the power source and a controller. The milling system can comprise: a rotor configured to rotate and remove an amount of material from a working area a drive member coupling the rotor to be driven by the power source; a tensioner assembly configured to tension the drive member; and a sensor configured to measure the tension of the drive member. The controller can be configured to, in response to a signal received from the sensor, determine if the rotor has encountered an object capable of damaging the rotor.

TECHNICAL FIELD

The present application relates generally, but not by way of limitation,to methods and systems for construction machines, such as rotary mixermachines and cold planar machines. More particularly, the presentapplication relates to systems and methods for monitoring load on arotor of such machines.

BACKGROUND

Rotary mixers can be used to recycle old or degraded pavement for reuseon the surfaces. Cold planer machines can be used to remove old ordegraded pavement from surfaces such as roadways and parking lots. Thesurfaces in such working areas can extend over various terrainsincluding surfaces that have grades (slopes) from the horizontal. Assuch, these machines can include systems for adjusting the verticalheight of the machine and a rotary cutting tool attached thereto inorder to, for example, control the cutting depth during millingoperations.

U.S. Pat. No. 7,353,105, entitled “Engine Control Device forConstruction Machinery” discloses construction machines that haveswitchable engine mode between normal operation and energy saving.Japanese Patent Application No. 07189764 discloses construction machinesthat adjust engine horsepower for work load to prevent engine stalling.

SUMMARY OF THE INVENTION

A machine for road work for road work, the machine can comprise: aframe, a drive system including a power source carried by the frame, amilling system driven by the power source and a controller. The millingsystem can comprise: a rotor configured to rotate and remove an amountof material from a working area a drive member coupling the rotor to bedriven by the power source; a tensioner assembly configured to tensionthe drive member; and a sensor configured to measure the tension of thedrive member. The controller can be configured to, in response to asignal received from the sensor, determine if the rotor has encounteredan object capable of damaging the rotor.

A method of monitoring a rotor of a working machine, the method cancomprise: providing a drive member coupling the rotor to be driven by adrive system of the working machine; sensing a pressure indicative of atension of the drive member; and determining if the rotor hasencountered an object capable of damaging the rotor based upon thesensing the pressure.

A system that can comprise: a frame, a drive system including a powersource, a milling system driven by the power source and a controller.The milling system can comprise: a rotor configured to rotate and removean amount of material from a working area, a belt configured to couplethe rotor to be driven by the power source, and a first sensorconfigured to measure a pressure of a hydraulic cylinder tensioning thebelt. The controller can be configured to, in response to a signalreceived from the first sensor, determine if the rotor has encounteredan object capable of damaging the rotor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a rotary mixer machine according toan example of the present application.

FIG. 2 is a perspective view of part of a milling system of the rotarymixer machine according to an example of the present application.

FIG. 3A is a graph of a pressure signal according to an example of thepresent application.

FIG. 3B is a graph of the pressure signal of FIG. 3A and a torque signalaccording to an example of the present application.

FIG. 3C is a graph of the pressure signal of FIG. 3A and a pulley speedsignal according to an example of the present application.

DETAILED DESCRIPTION

FIG. 1 is a schematic side view of rotary mixer machine 10 showing frame12 to which a drive system 13 including a power source 13A andtransportation devices (wheels) can be connected. The transportationdevices 16 can be connected to frame 12 via a plurality of legs 18 (alsoreferred to as lifting columns herein). The rotary mixer machine 10 hasa milling system 20 that is coupled to the underside of frame 12 betweentransportation devices 16. Although the present application is describedwith reference to a rotary mixer machine, the present invention isapplicable to other types of industrial machines, such as cold planermachines.

The frame 12 can longitudinally extend between front end 12A and rearend 12B along frame axis A. The power source 13A can be provided in anynumber of different forms including, but not limited to, internalcombustion engines, Otto and Diesel cycle internal combustion engines,electric motors, hybrid engines and the like. Power from the powersource 13A can be transmitted to various components and systems of thedrive system 13, such as the transportation devices 16, one or more ofthe plurality of legs 18, the milling system 20 and a controller 100.

The frame 12 can be supported by the transportation devices 16 via thelegs 18. Although shown as wheels, the transportation devices 16 can beany kind of ground-engaging device that allows rotary mixer machine 10to move over a surface 14 within a working area 15. Thus, the surface 14and working area 15 can be, for example, a paved road or a groundalready processed by rotary mixer machine 10. Thus, in alternativeembodiments, the transportation devices 16 could be configured as trackassemblies or crawlers. The transportation devices 16 can be configuredto move rotary mixer machine 10 in a forward travel and a backwardtravel along the ground surface in the direction of axis A. The legs 18can be vertically moveable (i.e. configured to raise and lower the frame12 and rotor 22 (also referred to as a drum)) relative to thetransportation devices 16 and the surface 14. The legs 18 can beconfigured to rotate to provide steering for the rotary mixer machine10.

The legs 18 can each comprise actuators such as a hydraulic liftingcolumn configured to raise and lower frame 12 to, for example, set adesired cutting depth of the rotor 22 of the milling system 20 and toraise the frame 12 and rotor 22 to accommodate rotary mixer machine 10engaging obstacles on the ground. These obstacles can be sensed orotherwise determined using the monitoring system 101 and techniques thatcan be used with the controller 100 as discussed subsequently. In somecases, the front two legs can operate independent of each other whilethe rear legs can be tied together with pressure balance and raise andlower together. Thus, the legs 18 can be vertically moveable legsconfigured to (in combination with the controller 100) maintain adesired attitude of the frame 12 and the rotor 22 relative to thesurface 14 of the working area 15.

As described herein, one or more of the plurality of legs 18 can becoupled to a hydraulic system that can be operated by the controller 100receiving feedback with the monitoring system 101, techniques and/or oneor more sensors (e.g., one or more hydraulic pressure sensors used asdrive member tension sensor(s), belt pulley speed sensor(s), drivemember speed sensor(s), torque sensor(s) or combinations thereof).

The milling system 20 can be connected to the frame 12 and can be partof the drive system 13 of the machine 10. The milling system 20 cancomprise the rotor 22, a housing 24 and a milling system actuator 25.The rotor 22 (sometimes called a milling drum or drum) is rotatablerelative to the frame 12 and the surface 14 and is operatively connectedto be driven by the power source. The rotor 22 can include a pluralityof cutting tools, such as chisels or bits, disposed thereon. The rotor22 can be rotated within the housing 24 about axis B extending in adirection perpendicular to frame axis A into the plane of FIG. 1. Asrotatable milling drum 22 spins or rotates about axis B, the cuttingtools may engage the surface 14, such as, for example, asphalt, ofexisting roadways, bridges, parking lots and the like. Moreover, as thecutting tools engage such the surface 14, the cutting tools removelayers of materials forming work surface, such as hardened dirt. Thespinning action of the rotor 22 and the cutting tools pulverizes andmixes an existing road surface (surface 14) and a predetermined amountof the underlying material in a rotor chamber formed by the housing 24to create a new base or a new road surface. Various additives oraggregates can be deposited on surfaces (including surface 14) or withinthe working area by the action of the rotor 22 and the cutting tools.Thus, the rotary mixer machine 10 of the present application can includesystems for depositing an additive, such as Portland cement, lime, flyash, cement kiln dust, etc., and/or water on the work surfaces duringthe mixing/pulverizing operations.

Referring now to FIG. 1, the housing 24 forms the chamber foraccommodating the rotor 22 and action of the rotor in pulverizing thesurface 14. The housing 24 can include front and rear walls, and a topcover positioned above the rotor 22. Furthermore, the housing 24 caninclude lateral covers, or side plates (these and other components ofthe milling system 20 are removed in FIG. 2), on the left and rightsides of the rotor 22 with respect to a travel direction of rotary mixermachine 10. The housing 24 is open toward the ground so that the rotor22 can engage the ground from within the housing 24.

The milling system 20 can also include the milling system actuator 25that can comprise a hydraulic cylinder or another device configured toraise and lower the rotor 22 to selectively disengage, engage, increaseor reduce the depth of cut the rotor 22 makes with the surface 14 of theworking area 15.

FIG. 2 shows additional components of the milling system 20 including agearbox 26, belt pulleys 28, a drive member 29 and a tensioner assembly30. The tensioner assembly 30 can include a hydraulic cylinder 32. InFIG. 2 components such as the housing 24 and portions of the rotor 22have been removed.

The gearbox 26 can be mechanically coupled to the drive system 13(FIG. 1) so as to be driven by the power source 13A. The gearbox 26includes a belt pulley 28A one of the belt pulleys 28. The belt pulleys28 are rotatable and can be configured to engage with an interior of thedrive member 29. The belt pulley 28A can be coupled to the gearbox 26for rotation therewith and can act to drive the drive member 29. Thedrive member 29 can comprise a closed loop belt, chain or othertensioned member fabricated of suitable material(s) and can beconfigured to loop over and be coupled to a second belt pulley 28B ofthe rotor 22. The second belt pulley 28B can be one of the belt pulleys28. Although the term “belt pulley” is used herein it should berecognized that the pulleys can have any configuration suitable for acoupling with drive member 29. Thus, if the drive member 29 is a chain,for example, the pulleys could be gears or another suitable mechanism.

The tensioner assembly 30 can include a third belt pulley 28C, thehydraulic cylinder 32, an arm 34 and a base 36. The base 36 can becoupled to the frame of the rotary mixer machine or to other parts ofthe milling system 20 such as the housing. The belt pulley 28C can beconfigured to engage and be coupled with the drive member 29 forrotation with movement of the drive member 29. The tensioner assembly 30can include the arm 34, which is moveably coupled to the base 36 such asvia pins or other mechanical mechanisms. The position of the arm 34 canbe moved relative to the base 36 by the hydraulic cylinder 32, which canbe coupled to the arm 34 at a first end thereof. For example, thehydraulic cylinder 32 can be extended to pivot the arm 34 relative tothe base 36 to put a degree of tension on the drive member 29 via thebelt pulley 28C. This degree of tension on the drive member 29 can beadjustable with movement of the arm 34 facilitated byextension/retraction of the end of the hydraulic cylinder 32.Extension/retraction of the end of the hydraulic cylinder 32 can beaccomplished by changing a pressure of the hydraulic fluid within thehydraulic cylinder 32.

According to the illustrated embodiment of FIG. 2, the milling system 20can include at least one pulley sensor 38 and at least one pressuresensor 40. A torque of the gearbox 26, rotor 22 or other portions of thedrive system 13 can also optionally be measured by one or more sensor(s)not specifically illustrated in FIG. 2 and can used with the monitoringsystem 101 and the controller 100.

The at least one pulley sensor 38 can be configured to measure criteriasuch as a rotational speed, acceleration, etc. of one or more of thebelt pulleys 28. From this data, a speed, acceleration, etc. of thedrive member 29 can be determined such as by the controller 100 (FIG.1). Similarly, the at least one pressure sensor 40 can be configured tomonitor pressure within the hydraulic cylinder 32. This pressure can beindicative of a tension of the drive member 29. Signals/data from the atleast one pulley sensor 38 and the at least one pressure sensor 40 canbe transmitted to the controller 100 (FIG. 1). Based upon one or more ofthese signals, the controller 100 can determine if the rotor 22 hasencountered an object capable of damaging the rotor 22. Although the atleast one pulley sensor 38 is illustrated in FIG. 2, according to otherembodiments other types and locations of sensor can be used to determinethe speed, acceleration, etc. of the drive member 29. For example, adistinctive marking(s) can be placed on the drive member 29 and atachometer or other visual sensor could be utilized to determine speed,acceleration, etc. of the drive member 29 by counting the number oftimes the marking(s) visually pass within range with movement of thedrive member 29. Additionally, although both the least one pulley sensor38 and the least one pressure sensor 40 are shown in the embodiment ofFIG. 2, it is contemplated that only one of these sensors need be usedin some embodiments to determine if the rotor has encountered an objectcapable of damaging the rotor.

Referring again to FIG. 1, one or more aspects of the rotary mixermachine 10, including monitoring system 101 can be managed by one ormore embedded or integrated controllers 100 of the rotary mixer machine10. The controller 100 can comprise one or more processors,microprocessors, microcontrollers, electronic control modules (ECMs),electronic control units (ECUs), or any other suitable means forelectronically monitoring and/or controlling functionality of the rotarymixer machine 10.

The controller 100 can be configured to operate according to apredetermined algorithm or set of instructions for monitoring andcontrolling the rotary mixer machine 10 based on various operatingconditions including, for example, input from the at least one pressuresensor 40 and/or the at least one pulley sensor 38.

It is further contemplated that the controller 100 can be configured tocontinuously perform various calculations such as determining if therotor has encountered an object capable of damaging the rotor in adynamic manner in real-time and output these to an interface and/or takeother actions.

Such algorithms or set of instructions can be stored in a database andcan be read into an on-board memory of the controller 100, orpreprogrammed onto a storage medium or memory accessible by thecontroller 100, for example, in the form of a hard drive, jump drive,optical medium, random access memory (RAM), read-only memory (ROM), orany other suitable computer readable storage medium commonly used in theart (each referred to as a “database”).

The controller 100 can be in electrical communication or connected tothe milling system 20, drive system 13, or the like and various othercomponents, systems or sub-systems of rotary mixer machine 10. By way ofsuch connection, the controller 100 can receive data pertaining to thecurrent operating parameters of the rotary mixer machine 10 fromsensors, such as a torque sensor(s), the at least one pressure sensor 40and/or the at least one pulley sensor 38, and the like. In response tosuch input, the controller 100 may perform various determinations andtransmit output signals corresponding to the results of suchdeterminations or corresponding to actions that need to be performed,such as producing up and down movements of the legs 18 (thereby raisingthe rotor 22), raising the rotor 22 with an actuator, or disconnectingthe rotor 22 from being driven by the drive system 13 as desired. Thus,the controller 100 can be configured to automatically activate variousactuators or perform other actions to protect components such as therotor 22.

As shown in FIG. 3A, according to one embodiment the controller 100 canbe configured to receive a signal 102 indicative of a pressure withinthe hydraulic cylinder 32 (FIG. 2). This pressure can be sensed and thesignal generated with the at least one pressure sensor 40 (FIG. 2). FIG.3A shows a graph of the signal indicative of the pressure during therotor has encountered an object capable of damaging the rotor. As shownin the graph of FIG. 3A, the signal 102 has a region 104 where thepressure of the hydraulic cylinder decreases by 10% or more from a meanpressure when the rotor has initially encountered the object capable ofdamaging the rotor. The graph also has a region 106 where the pressureincreases by at least 25% as compared to the mean pressure. The region104 and the region 106 occur within 0.2 seconds or less of one another.However, other time intervals between regions 104 and 106 arecontemplated based upon operating conditions.

According to one embodiment, the controller 100 can be configured to, inresponse to the signal 102 received from the at least one pressuresensor 40, determine if the rotor has encountered an object capable ofdamaging the rotor. For example, the controller 100 can make thisdetermination by determining if the pressure decreases by at least 5%,at least 10%, at least 15%, at least 20%, at least 25%, etc. as comparedto the mean pressure. Alternatively or additionally, the controller 100can make this determination by determining if the pressure increases byat least 10%, at least 15%, at least 20%, at least 25%, at least 30%, atleast 35%, at least 40%, at least 50%, at least 60%, at least 75% atleast 100%, etc. as compared to the mean pressure. In yet furtherembodiments, the controller 100 can make this determination bydetermining if the pressure decreases by at least 5% (or anotherpercentage such as at least 10%, at least 15%, at least 20%, at least25%) as compared to the mean pressure and the pressure then increases byat least 20% (or another percentage such as at least 10%, at least 15%,at least 25%, at least 30%, at least 35%, at least 40%, at least 50%, atleast 60%, at least 75%, at least 100%) as compared to the mean pressurewithin 0.2 seconds or less or another designated time interval such as,but not limited to (0.025 seconds or less, 0.04 seconds or less, 0.06seconds or less, 0.08 seconds or less, 0.1 seconds or less, 0.12 secondsor less, 0.14 seconds or less, 0.16 seconds or less, 0.18 seconds orless, 0.22 seconds or less, 0.24 seconds or less, 0.26 seconds or less,0.28 seconds or less, 0.30 seconds or less, 0.35 seconds or less, 0.4seconds or less, 0.5 seconds or less, 0.75 seconds or less, 1.0 secondsor less, etc.).

It should be noted that in other contemplated embodiments where thehydraulic cylinder 32 and the tensioner assembly 30 are positioned in adifferent manner from the arrangement of FIG. 2 (such as an invertedarrangement relative to the arrangement of FIG. 2) that the pressurewithin the hydraulic cylinder 32 may initially increase if the rotor hasencountered an object capable of damaging the rotor. Thus, in suchembodiments the controller 100 can be configured to, in response to asignal (such signal being different from that of signal 102) receivedfrom the at least one pressure sensor 40, determine if the rotor hasencountered an object capable of damaging the rotor. For example, thecontroller 100 can make this determination by determining if thepressure increases by at least 5%, at least 10%, at least 15%, at least20%, at least 25%, etc. as compared to the mean pressure. In yet furtherembodiments, the controller 100 can make this determination bydetermining if the pressure increases by at least 5% (or anotherpercentage such as at least 10%, at least 15%, at least 20%, at least25%) as compared to the mean pressure and the pressure then decreases byat least 20% (or another percentage such as at least 10%, at least 15%,at least 25%, at least 30, at least 35%, at least 40%, at least 50%, atleast 60%, at least 75%, at least 100%) as compared to the mean pressurewithin 0.2 seconds or less or another designated time interval such as,but not limited to (0.025 seconds or less, 0.04 seconds or less, 0.06seconds or less, 0.08 seconds or less, 0.1 seconds or less, 0.12 secondsor less, 0.14 seconds or less, 0.16 seconds or less, 0.18 seconds orless, 0.22 seconds or less, 0.24 seconds or less, 0.26 seconds or less,0.28 seconds or less, 0.30 seconds or less, 0.35 seconds or less, 0.4seconds or less, 0.5 seconds or less, 0.75 seconds or less, 1.0 secondsor less, etc.).

FIG. 3B shows an alternative embodiment where both the signal 102indicative of the pressure within the hydraulic cylinder 32 (FIG. 2) isgraphically shown and a signal 108 indicative of torque of the drivesystem 13 (FIG. 1) is graphically shown. The signal 108 can be from atorque sensor of the drive system 13 as discussed previously. The signal108 has a region 110 where the torque of the drive system torque thenincreases by 50% or more relative to a mean torque when the rotor hasinitially encountered the object capable of damaging the rotor. Thegraph also has a region 112 where the torque then decreases by at least10% from a mean torque or more relative to the mean torque. The regions110 and 112 occur within 0.2 seconds or less of one another andcorrespond generally at the same time and over the same time period withthe regions 104 and 106 of the signal 102. However, other time intervalsbetween regions 110 and 112 are contemplated based upon operatingconditions.

According to one embodiment, the controller 100 can be configured to, inresponse to the signals 102 and 108 received from the at least onepressure sensor 40 and the torque sensor, determine if the rotor hasencountered an object capable of damaging the rotor. For example, thecontroller 100 can make this determination by determining if thepressure decreases by at least 5%, at least 10%, at least 15%, at least20%, at least 25%, etc. as compared to the mean pressure and if thetorque increases by 50% or more (or another value such as 25% or more,35% or more, 75% or more, 100% or more, 125% or more, 150% or more, 200%or more, 300% or more, 500% or more, 600% or more, etc.) as compared toa mean torque during a corresponding (substantially the same time andsame length of time) time. Alternatively or additionally, the controller100 can make this determination by determining if the pressure increasesby at least 10%, (or another values such as at least 15%, at least 20%,at least 25%, at least 30%, at least 35%, at least 40%, at least 50%, atleast 60%, at least 75% at least 100%, etc.) as compared to the meanpressure and the torque decreases by at least 10% (or another value suchas at least 5%, at least 15%, at least 25%, at least 50%) as comparedwith the mean torque during the corresponding time.

FIG. 3C show yet another alternative embodiment where both the signal102 indicative of the pressure within the hydraulic cylinder 32 (FIG. 2)is graphically shown and a signal 116 indicative of a speed of the drivemember 29 (FIG. 2) is graphically shown. The signal 116 can be from theat least one pulley sensor 38 (FIG. 2) or another sensor as discussedpreviously. The signal 116 has a region 118 where the speed of the drivemember decreases by at least 10% as compared to a mean drive memberspeed when the rotor has initially encountered the object capable ofdamaging the rotor. The graph also has a region 120 where the drivemember speed increases by at least 10% as compared to the mean drivemember speed. The regions 118 and 120 occur within 0.2 seconds or lessof one another and correspond generally at the same time and over thesame time period with the regions 104 and 106 of the signal 102.However, other time intervals between regions 118 and 120 arecontemplated based upon operating conditions

According to one embodiment, the controller 100 can be configured to, inresponse to the signals 102 and 116 received from the at least onepressure sensor 40 and the at least one pulley sensor 38, determine ifthe rotor has encountered an object capable of damaging the rotor. Forexample, the controller 100 can make this determination by determiningif the pressure decreases by at least 5%, at least 10%, at least 15%, atleast 20%, at least 25%, etc. as compared to the mean pressure and ifthe speed decreases by at least 10% (or another value such as at least5%, at least 7%, at least 10%, at least 15%, at least 20%, at least 25%,at least 30%, at least 50, etc.) as compared a mean drive member speedduring a corresponding (substantially the same time and same length oftime) time. Alternatively or additionally, the controller 100 can makethis determination by determining if the pressure increases by at least10%, (or another values such as at least 15%, at least 20%, at least25%, at least 30%, at least 35%, at least 40%, at least 50%, at least60%, at least 75% at least 100%, etc.) as compared to the mean pressureand the speed increases by at least 10% (or another value such as atleast 5%, at least 15%, at least 25%, at least 50%) as compared with themean torque during the corresponding time period.

The controller 100 can include various output devices, such as screens,video displays, monitors and the like that can be used to displayinformation, warnings, data, such as text, numbers, graphics, icons andthe like, regarding the status of the machine 10. The controller 100,including operator interface, can additionally include a plurality ofinput interfaces for receiving information and command signals fromvarious switches and sensors associated with the rotary mixer machine 10and a plurality of output interfaces for sending control signals tovarious actuators associated with the rotary mixer machine 10. Suitablyprogrammed, the controller 100 can serve many additional similar orwholly disparate functions as is well-known in the art. As discussedpreviously, the controller can be configured to control the machine 10to at least one of decouple the milling system 20 from being driven bythe power source, activate a first actuator configured to raise therotor relative to a surface of the working area or activate a secondactuator to raise the frame relative to the surface thereby raising therotor, in response to determining the rotor has encountered the objectcapable of damaging the rotor.

INDUSTRIAL APPLICABILITY

The present application describes various apparatuses, systems andmethods for a rotary mixer machine 10 or cold planer machine. These caninclude a controller or method of monitoring and controlling thatdetermines if the rotor has encountered an object capable of damagingthe rotor. The disclosed apparatuses, system and methods can be used toprotect components such as the rotor 22 and other parts of the millingsystem 20 (such as the drive member 29) and/or drive system 13 fromdamage, thereby providing cost savings and reducing down time forrepair. For example, techniques disclosed herein include, when thecontroller 100 or method of monitoring and controlling determines therotor has encountered an object capable of damaging the rotor variousactions can automatically be taken. For example, the controller 100 cancommand a decoupling of the milling system from being driven by thepower source, activate a first actuator configured to raise the rotorrelative to a surface of the working area or activate a second actuatorto raise the frame relative to the surface thereby raising the rotor.

This determination can be made using signal(s) from one or more sensorsof the milling system 20 such as at least one pressure sensor 40, the atleast one pulley sensor 38 and/or the torque sensor. The presentinventors have recognized, as discussed above, for example, that apressure in a drive member tension cylinder (indicative of tension onthe drive member) drops (or in other configurations increases) when atorque spike is seen in the drive system. This is seen as region 104 inFIG. 3A, for example. A pressure spike (or drop in alternativeconfigurations) is also seen just after the high torque event. This isseen at region 106 in FIG. 3A. These pressure changes can be usedindividually, together with one another, or in combination with othersensed criteria (e.g., sensed torque, sensed belt/pulley speed, sensedbelt/pulley acceleration, etc.) to sense and identify a torque spikesuch that the actions discussed above can be commanded by the controller100.

What is claimed is:
 1. A machine for road work, the machine comprising:a frame; a drive system including a power source carried by the frame; amilling system driven by the power source, the milling systemcomprising: a rotor configured to rotate and remove an amount ofmaterial from a working area; a drive member coupling the rotor to bedriven by the power source; a tensioner assembly configured to tensionthe drive member; and a sensor configured to measure the tension of thedrive member; and a controller configured to, in response to a signalreceived from the sensor, determine if the rotor has encountered anobject capable of damaging the rotor.
 2. The machine of claim 1, whereinthe tensioner assembly includes a hydraulic cylinder, and wherein thesensor comprises a pressure sensor configured to measure a pressure ofthe hydraulic cylinder as indicative of the tension of the drive member.3. The machine of claim 2, wherein the pressure of the hydrauliccylinder decreases by 10% or more from a mean pressure when the rotorhas initially encountered the object capable of damaging the rotor. 4.The machine of claim 3, wherein the controller determines if the rotorhas encountered the object capable of damaging the rotor by one or moreof: determining if the pressure decreases by at least 10% as compared tothe mean pressure; determining if the pressure increases by at least 25%as compared to the mean pressure; or determining if the pressuredecreases by at least 5% as compared to the mean pressure and thepressure then increases by at least 20% as compared to the mean pressurewithin 0.2 seconds or less.
 5. The machine of claim 1, furthercomprising a second sensor configured to measure one of a speed of thedrive member or a torque of the drive system.
 6. The machine of claim 5,wherein the controller is configured to, in response to the signalreceived from the sensor and a signal received from the second sensor,determine if the rotor has encountered the object capable of damagingthe rotor.
 7. The machine of claim 6, wherein the controller determinesif the rotor has encountered the object capable of damaging the rotor byone or more of: determining if the torque increases by 50% or more ascompared a mean torque and the pressure reduces by at least 10% ascompared to the mean pressure within a corresponding time frame; ordetermining if the speed of the drive member decreases by at least 10%as compared to a mean drive member speed and the pressure reduces by atleast 10% as compared to the mean pressure within the corresponding timeframe.
 8. The machine of claim 1, wherein the controller is configuredto control the machine to at least one of decouple the milling systemfrom being driven by the power source, activate a first actuatorconfigured to raise the rotor relative to a surface of the working areaor activate a second actuator to raise the frame relative to the surfacethereby raising the rotor, in response to determining the rotor hasencountered the object capable of damaging the rotor.
 9. A method ofmonitoring a rotor of a working machine, the method comprising:providing a drive member coupling the rotor to be driven by a drivesystem of the working machine; sensing a pressure indicative of atension of the drive member; and determining if the rotor hasencountered an object capable of damaging the rotor based upon thesensing the pressure.
 10. The method of claim 9, further comprisingautomatically controlling the machine by at least one of decoupling thedrive member from being driven by the drive system, activating a firstactuator configured to raise the rotor relative to a surface of theworking area or activating a second actuator to raise a frame relativeto the surface thereby raising the rotor, in response to determining therotor has encountered the object capable of damaging the rotor.
 11. Themethod of claim 9, wherein determining if the rotor has encountered theobject capable of damaging the rotor based upon the sensing the pressurecomprises one or more of: determining if the pressure decreases by atleast 10% as compared to the mean pressure; determining if the pressureincreases by at least 25% as compared to the mean pressure; ordetermining if the pressure decreases by at least 5% as compared to amean pressure and the pressure then increases by at least 20% ascompared to the mean within 0.2 seconds or less.
 12. The method of claim9, further comprising sensing a speed of the drive member or a torque ofthe drive system, and the determining the rotor has encountered theobject capable of damaging the rotor is based upon the sensing thepressure and the sensing the speed of the drive member or the torque ofthe drive system.
 13. The method of claim 12, wherein determining if therotor has encountered the object capable of damaging the rotor basedupon the sensing the pressure and the sensing the speed of the drivemember or the torque of the drive system comprises one or more of:determining if the torque increases by 50% or more as compared a meantorque and the pressure reduces by at least 10% as compared to the meanpressure within 0.2 seconds or less; or determining if the speed of thedrive member decreases by at least 100% as compared to a mean drivemember speed and the pressure reduces by at least 10% as compared to themean pressure within 0.2 seconds or less.
 14. A system comprising: aframe; a drive system including a power source; a milling system drivenby the power source, the milling system comprising: a rotor configuredto rotate and remove an amount of material from a working area; a beltconfigured to couple the rotor to be driven by the power source; and afirst sensor configured to measure a pressure of a hydraulic cylindertensioning the belt; and a controller configured to, in response to asignal received from the first sensor, determine if the rotor hasencountered an object capable of damaging the rotor.
 15. The system ofclaim 14, wherein the pressure of the hydraulic cylinder decreases by10% or more from a mean pressure when the rotor has initiallyencountered an object capable of damaging the rotor.
 16. The system ofclaim 15, wherein the controller determines if the rotor has encounteredthe object capable of damaging the rotor by one or more of: determiningif the pressure decreases by at least 10% as compared to the meanpressure; determining if the pressure increases by at least 25% ascompared to the mean pressure; or determining if the pressure decreasesby at least 5% as compared to a mean pressure and the pressure thenincreases by at least 20% as compared to the mean within 0.2 seconds orless.
 17. The system of claim 1, further comprising a second sensorconfigured to measure one of a speed of the belt or a torque of thedrive system.
 18. The system of claim 17, wherein the controller isconfigured to, in response to the signal received from the sensor and asignal received from the second sensor, determine if the rotor hasencountered the object capable of damaging the rotor.
 19. The system ofclaim 18, wherein the controller determines if the rotor has encounteredthe object capable of damaging the rotor by one or more of: determiningif the torque increases by 100% or more as compared a mean torque andthe pressure reduces by at least 10% as compared to the mean pressurewithin 0.2 seconds or less; or determining if the speed of the beltdecreases by at least 10% as compared to a mean belt speed and thepressure reduces by at least 10% as compared to the mean pressure within0.2 seconds or less.
 20. The system of claim 14, wherein the controlleris configured to control the machine to at least one of decouple themilling system from being driven by the power source, activate a firstactuator configured to raise the rotor relative to a surface of theworking area or activate a second actuator to raise the frame relativeto the surface thereby raising the rotor, in response to determining therotor has encountered the object capable of damaging the rotor.